One day I was analyzing an email campaign weeks after the campaign had dropped and learned something really interesting. I usually grab the results of a campaign a few days after it drops so any insights or learnings can be built into the next campaign. But, I had been on vacation for a week, came back to over 800 emails and by the time I dug out this campaign was 3 weeks over.

But it wasn’t “over”.

Pulling the results I noticed that this 3 week old email was still getting some significant clicks. And there were small spikes in clicks on the same day we drop our weekly emails. It became very apparent that these emails were still hanging around in peoples in boxes and when they get the next weekly email it reminds them to open previous weeks’.

So that old email, just sittin’ there takin’ up space like the octogenarian at the diner who only orders coffee but uses the booth for 3 hours – actually has value.

So I did a little study of three different emails in 3 different web properties in 3 different countries and found (I can’t give you specifics) that between 10 and 20% of clicks were 7-30 days after the initial email drop. Also, 9 to 14% of the total clicks were from unique clickers meaning the vast majority of these old clicks were from people who had not opened the email before. So this is fresh content to them.

So what’s lesson here? This begs for a test. I would do an immediacy vs. mellowness test. If up to 20% of openers are opening after 7 days then any offer that’s “limited time” would be a message lost on them. Conversely, a long running offer could inspire a reaction of “this email is OLD. I can’t believe this offer’s still good!”.

Here’s the test I would conduct: one email has a very strong message -Limited time offer! It should be an aggressive offer of high value good for 48 hours only. Another email should have a less aggressive offer that’s good for 30 days. Who knows? Maybe the energy and spryness of a live hard, die young marketing message is actually trumped by an email that’s old and in the way.

$6 BILLION dollars wasn’t enough? $6 billion, with a “b”. The YouTube guys got $1.6 billion back in 2006 and they seem perfectly content padding around the mansion in gold plated bunny ear slippers. $6 billion buys a lot of Skittles and beer.

Here’s why you’re going to look back on this in a few years and wonder how you could have been so short sighted.

1- Your business model has a very low barrier to entry. I currently subscribe to your emails and Living Social’s emails. The other day a 3rd email newsletter normally not geared to coupons had a social deal in it. Anyone can get in on this game. Expect a dozen competitors in your space by the end of 2011 including….

2- Google. You teased and poked the bear, he’s awake, he’s pissed and he’s hungry. Scorned, Google is building out their own coupon / social platform. I’m sure you heard. Combining their 70% search market share with a decent user interface and you’ll never compete with the variety and specifically targeted deals they could come up with. They know that I search for Mexican restaurants in zip code 10003 on Wednesdays – BOOM! A perfectly tailored deal for half off a pitcher of margaritas is sent to me. Do you know what kind of deals I would like to increase my take rate? Clearly not, because your deals are 93% girly stuff I would never buy. I remember even telling you I was a dude when I signed up and yet you keep serving me coupons for spa treatments and stretch mark removal services and pole dancing classes. Dude, I’m A DUDE!

But Google is not infallible. Let’s say that they screw it up and their proprietary platform goes nowhere like Google Video or Buzz or Wave. They have so much cash they’ll just buy up all the coupon sites that did get it right and infuse them with enough cash to crush you. What do you think $6 billion smells like? Imagine what it smells like because that’s as close as you’re going to get to that kind of money again.

3- The internet has a short memory and a hugely inflated sense of worth. This past summer Lycos was sold for the 3rd time. Remember Lycos? No? It was a search engine. A search engine that sold for $12.5 billion in 2000, $95 million in 2004 and recently sold again for $36 million. I suspect in 3 years time Groupon will be spoken in the same breath as Alta Vista, Friendster, MySpace and pets.com.

You’ve got moxie, Groupon. I have to give you that. But I think you watched The Karate Kid a few too many times, because often in life the little guy doesn’t win.